A study in the October issue of the journal Obstetrics and Gynecology suggests that regular use of aspirin can help women prevent the development of ovarian cancer, Reuters Health reports. Researchers at the University of South Florida College of Medicine treated ovarian cancer cells with varying doses of aspirin and found that doses of five millimoles per liter or higher slowed cancer cell growth by 68%. Lower doses were not effective. It's not clear how aspirin works to slow cancer growth, but the researchers believe that the widely used compound may block a key enzyme found in high concentrations in many types of cancerous cells.